Upgrades Without the Downtime

Migration and Upgrades Across Thousands of VMs Results in Zero Downtime


Category: Case Study
Vertical: Healthcare
Est. Read Time: 4 min.

Timelines met in a timely fashion.

Discover the advantages decades of experience can bring.

A focus on IT platforms, not IT components.

Our expertise and instant access to expert level technical resources provided a smooth integration of services for our client.

Preparation and Experience – The Secret to a Seamless Upgrade from Sayers

When their internal team was lacking bandwidth and 2,000 VMs were in need of an upgrade, our client turned to Sayers to get the job done with little to no downtime across all of the VMs.

When VMWare 5.5 went EOL, a client was looking to migrate thousands of VMs. However, the client’s team didn’t have the resource bandwidth to tackle a project of this size.  Enter Sayers.

Jumping from VMWare 5.5 to 6.0 or better was a massive undertaking for a client of this size. With thousands of migrating machines on premise support was required and establish strong project management processes to see the upgrade stayed on scheduled and without interruption.

The Sayers expertise with this type of migration helped coordinate the client’s resources, develop a consistent process across the multiple application owners, and communicate with business owners, technical staff, and Sayers engineers to ensure coordination during every step of the way.

 The assignment given to Sayers was:

  • Migration of 2,000 VMs from 5.5 to 6.5 VMWare
  • Leverage the same storage and networking equipment currently in place
  • Distributed switching on both old and new environment


While typically a VMware environment upgrade from 5.5 to 6.5 would be fairly rudimentary if the vCenter for the environment were upgraded, for this case a new 6.5 environment was built alongside the 5.5 environment and thus the VMs needed to be moved from a 5.5 environment to a separate 6.5 environment. Given that and given distributed switching was in place, there were some technical challenges to accomplishing the moves. The swing hosts used for moving VMs from environment to environment, had to be converted from distributed switches to standard switches, which required all the VMs on the host needed to have their network connections swung from existing distributed port groups to standard port groups, and then once moved to the new environment, the process needed to be reversed.


The results of the assignment were:

  • Successful migration of all VMs
  • ZERO downtime across any of the moved VMs
  • Spared reallocation of resources for the client
  • Improved visibility for app owners across the VMWare environment
  • Change management processes to alleviate product speed bumps


The overall result was nothing short of a flawless delivery by the technical teams involved. Client executives didn’t even notice the migration occurred because the downtime was nonexistent—largely in part to the preparation and experience of the project team.

With aging software that was nearing end-of-life, Sayers provided a solution to upgrade the software to provide more stability and features for years to come. In other words, a successful upgrade without the downtime.